Photo Credit: Braden Jarvis

West Kaua’i

Today: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 86 to 92 near the shore to around 78 above 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Tonight: Mostly clear. Isolated showers in the evening, then scattered showers after midnight. Lows around 72 near the shore to around 62 above 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

Thursday: Mostly sunny. Scattered showers in the morning, then isolated showers in the afternoon. Highs 87 to 92 near the shore to around 78 above 3000 feet. East winds 10 to 15 mph. Chance of rain 50 percent.

South Kaua’i

Today: Partly sunny. Breezy. Showers likely in the morning, then scattered showers in the afternoon. Highs 84 to 91. East winds 15 to 25 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then showers likely after midnight. Lows around 73. Northeast winds 15 to 25 mph. Chance of rain 70 percent.

Thursday: Partly sunny. Breezy. Showers likely in the morning, then scattered showers in the afternoon. Highs 85 to 91. East winds 15 to 25 mph. Chance of rain 70 percent.

Kaua’i Mountains

Today: Mostly cloudy. Breezy. Occasional showers in the morning, then scattered showers in the afternoon. Highs 74 to 85 in the valleys to around 68 above 4000 feet. East winds 15 to 25 mph. Chance of rain 90 percent.

Tonight: Mostly cloudy. Breezy. Showers likely in the evening, then occasional showers after midnight. Lows around 69 in the valleys to around 60 above 4000 feet. East winds 10 to 25 mph. Chance of rain 90 percent.

Thursday: Mostly cloudy. Breezy. Occasional showers in the morning, then scattered showers in the afternoon. Highs 74 to 85 in the valleys to around 68 above 4000 feet. East winds 10 to 20 mph. Chance of rain 90 percent.

North Kaua’i

Today: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs 77 to 89. East winds 10 to 20 mph. Chance of rain 50 percent.

Tonight: Breezy. Mostly cloudy with scattered showers. Lows 66 to 74. East winds 10 to 20 mph. Chance of rain 50 percent.

Thursday: Partly sunny in the morning then becoming mostly sunny. Breezy. Scattered showers. Highs 77 to 89. East winds 10 to 20 mph. Chance of rain 50 percent.

East Kaua’i

Today: Breezy. Mostly cloudy with showers likely in the morning, then mostly sunny with scattered showers in the afternoon. Highs 74 to 87. East winds 15 to 20 mph. Chance of rain 70 percent.

Tonight: Mostly cloudy. Breezy. Scattered showers in the evening, then showers likely after midnight. Lows 66 to 78. East winds 15 to 20 mph. Chance of rain 70 percent.

Thursday: Breezy. Mostly cloudy with showers likely in the morning, then mostly sunny with scattered showers in the afternoon. Highs 75 to 88. East winds 15 to 20 mph. Chance of rain 70 percent.

Detailed Forecast

Synopsis

Locally breezy trade winds will persist the next day or two, then ease slightly as we head into the weekend. An increase in wind speeds is possible early next week, with the potential for locally strong trades. Expect the trades to deliver brief windward showers to favor night and morning hours, with leeward areas remaining mostly dry. The exception will be the Big Island's leeward slopes, where afternoon clouds and showers will linger into the night before diminishing.

Discussion

Trade winds will prevail through the forecast period, with some fluctuations in speed anticipated into next week. A strong high pressure cell currently centered far N of the islands will support a locally breezy trade wind flow through Thursday. A subtle decrease in trade wind speeds is expected toward the end of the week as the high splits into two centers, NW and NE of the islands. Several weak lows passing between the two highs will weaken the ridge to the N, leading to the slightly weaker trades. Little significant change to the rainfall pattern is anticipated into the weekend, as a nearby mid-level ridge supports a strong subsidence inversion with an average base of about 7000'. Random pockets of shallow moisture will deliver brief windward showers that will tend to favor nights and mornings.
A weak tropical disturbance is about 1500 miles ESE of the Big Island this morning (near 12N133W), with Hurricane Dora located about 2800 miles away, with both tracking W near 15 mph. Moisture associated with the disturbance is expected to spread northward over the coming days, potentially interacting with a developing low aloft NW of the islands late this weekend, bringing an increase in trade showers.
Latest forecast from the National Hurricane Center in Miami, Florida indicates that Hurricane Dora will cross 140W, and into the central Pacific late this weekend. Thereafter, Dora is expected to move on a path that would generally keep it well S of the islands early next week. This scenario would bring an increase in trade wind speeds Monday and Tuesday. As a deep-layer high to the NE builds westward, winds could become strong as the trade wind flow becomes quite dry. With KBDI (Keetch-Byram Drought Index) values potentially exceeding 600 for the first time this summer by that time, Red Flag conditions could be met.

Aviation

High pressure north of the islands will maintain moderate to locally breezy trade winds for the next several days. AIRMET Tango for mountain lee turbulence will likely remain posted beyond the next 24 hours.
Clouds and showers will continue to favor windward and mauka areas, with slightly greater coverage and intensity through the early morning hours. VFR conditions will prevail, with occasional MVFR possible under passing showers.

Marine

High pressure far north of the state is driving fresh to locally strong trade winds through Thursday. A Small Craft Advisory (SCA) remains in effect through Thursday afternoon for the typically windy waters around Maui County and the Big Island. Trades will slightly decrease towards the end of the week as the high subtly weakens and shifts back to the west.
A small long period southwest swell has leveled off as a second pulse from the southwest is expected to arrive today keeping surf heights elevated through Thursday before steadily declining into the weekend. Choppy surf will remain along east facing shores before slightly declining by the end of the week. The potential for a near advisory east swell may be generated by Hurricane Dora that will impact east facing shores early next week. This east swell remains highly reliant on Dora's track, intensity, and size of the fetch. Stay tuned for more details as this system continues to move west.
Statewide water levels continue to be running higher than predicted (0.3 to 0.6 ft), combined with some of the highest tides of the year (near 3 feet). Minor coastal flooding is expected in the typical vulnerable low lying coastal areas and beaches during the peak high tides during the afternoon hours through Thursday. Please refer to the latest Coastal Flood Statement (CFWHFO) for more details.

HFO Watches/Warnings/Advisories

Small Craft Advisory until 6 PM HST Thursday for Maalaea Bay, Pailolo Channel, Alenuihaha Channel, Big Island Leeward Waters, Big Island Southeast Waters.

Data Courtesy of NOAA.gov